docs/latex/wx/bufferdc.tex

   1 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
   2 %% Name:        bufferdc.tex
   3 %% Purpose:     wxBufferedDC documentation
   4 %% Author:      Vadim Zeitlin
   5 %% Modified by:
   6 %% Created:     07.02.04
   7 %% RCS-ID:      $Id$
   8 %% Copyright:   (c) 2004 Vadim Zeitlin
   9 %% License:     wxWidgets license
  10 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  11
  12 \section{\class{wxBufferedDC}}\label{wxbuffereddc}
  13
  14 This simple class provides a simple way to avoid flicker: when drawing on it,
  15 everything is in fact first drawn on an in-memory buffer (a
  16 \helpref{wxBitmap}{wxbitmap}) and then copied to the screen only once, when this
  17 object is destroyed.
  18
  19 It can be used in the same way as any other device context. wxBufferedDC itself
  20 typically replaces \helpref{wxClientDC}{wxclientdc}, if you want to use it in
  21 your \texttt{OnPaint()} handler, you should look at
  22 \helpref{wxBufferedPaintDC}{wxbufferedpaintdc}.
  23
  24 \wxheading{Derived from}
  25
  26 \helpref{wxMemoryDC}{wxmemorydc}\\
  27 \helpref{wxDC}{wxdc}\\
  28 \helpref{wxObject}{wxobject}
  29
  30 \wxheading{Include files}
  31
  32 <wx/dcbuffer.h>
  33
  34 \wxheading{See also}
  35
  36 \helpref{wxDC}{wxdc}
  37
  38
  39 \latexignore{\rtfignore{\wxheading{Members}}}
  40
  41 \membersection{wxBufferedDC::wxBufferedDC}\label{wxbuffereddcctor}
  42
  43 \func{}{wxBufferedDC}{\void}
  44
  45 \func{}{wxBufferedDC}{\param{wxDC *}{dc}, \param{const wxSize\& }{area}}
  46
  47 \func{}{wxBufferedDC}{\param{wxDC *}{dc}, \param{const wxBitmap\& }{buffer}}
  48
  49 If you use the first, default, constructor, you must call one of the
  50 \helpref{Init}{wxbuffereddcinit} methods later in order to use the object.
  51
  52 The other constructors initialize the object immediately and \texttt{Init()}
  53 must not be called after using them.
  54
  55 \wxheading{Parameters}
  56
  57 \docparam{dc}{The underlying DC: everything drawn to this object will be
  58 flushed to this DC when this object is destroyed.  You may pass NULL
  59 in order to just initialize the buffer, and not flush it.}
  60
  61 \docparam{area}{The size of the bitmap to be used for buffering (this bitmap is
  62 created internally when it is not given explicitly).}
  63
  64 \docparam{buffer}{Explicitly provided bitmap to be used for buffering: this is
  65 the most efficient solution as the bitmap doesn't have to be recreated each
  66 time but it also requires more memory as the bitmap is never freed. The bitmap
  67 should have appropriate size, anything drawn outside of its bounds is clipped.}
  68
  69
  70 \membersection{wxBufferedDC::Init}\label{wxbuffereddcinit}
  71
  72 \func{void}{Init}{\param{wxDC *}{dc}, \param{const wxSize\& }{area}}
  73
  74 \func{void}{Init}{\param{wxDC *}{dc}, \param{const wxBitmap\& }{buffer}}
  75
  76 These functions initialize the object created using the default constructor.
  77 Please see \helpref{constructors documentation}{wxbuffereddcctor} for details.
  78
  79
  80 % VZ: UnMask() intentionally not documented, we might want to make it private
  81
  82
  83 \membersection{wxBufferedDC::\destruct{wxBufferedDC}}\label{wxbuffereddcdtor}
  84
  85 Copies everything drawn on the DC so far to the underlying DC associated with
  86 this object, if any.
  87
  88
  89 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  90
  91 \section{\class{wxBufferedPaintDC}}\label{wxbufferedpaintdc}
  92
  93 This is a subclass of \helpref{wxBufferedDC}{wxbuffereddc} which can be used
  94 inside of an \texttt{OnPaint()} event handler. Just create an object of this class instead
  95 of \helpref{wxPaintDC}{wxpaintdc} and that's all you have to do to (mostly)
  96 avoid flicker. The only thing to watch out for is that if you are using this
  97 class together with \helpref{wxScrolledWindow}{wxscrolledwindow}, you probably
  98 do \textbf{not} want to call \helpref{PrepareDC}{wxscrolledwindowpreparedc} on it as it
  99 already does this internally for the real underlying wxPaintDC.
 100
 101 \wxheading{Derived from}
 102
 103 \helpref{wxMemoryDC}{wxmemorydc}\\
 104 \helpref{wxDC}{wxdc}\\
 105 \helpref{wxObject}{wxobject}
 106
 107 \wxheading{Include files}
 108
 109 <wx/dcbuffer.h>
 110
 111
 112 \latexignore{\rtfignore{\wxheading{Members}}}
 113
 114 \membersection{wxBufferedPaintDC::wxBufferedPaintDC}\label{wxbufferedpaintdcctor}
 115
 116 \func{}{wxBufferedPaintDC}{\param{wxWindow *}{window}, \param{const wxBitmap\& }{buffer = wxNullBitmap}}
 117
 118 As with \helpref{wxBufferedDC}{wxbuffereddcctor}, you may either provide the
 119 bitmap to be used for buffering or let this object create one internally (in
 120 the latter case, the size of the client part of the window is used).
 121
 122
 123 \membersection{wxBufferedPaintDC::\destruct{wxBufferedPaintDC}}\label{wxbufferedpaintdcdtor}
 124
 125 Copies everything drawn on the DC so far to the window associated with this
 126 object, using a \helpref{wxPaintDC}{wxpaintdc}.
 127
 128